I am using a local server/client setup to test a point rendering program I have written. The client receives data points from the server correctly, however due to the high volume of data points that need to be processed, I have used the System.Threading.Tasks library to employ multithreading to process the data faster.
The output of the program should look like this (which currently takes an hour to process):
However, when using my multithreaded solution, it comes out like this:
The code I have used to setup the multithreading is below (initialisation and such is taken care of above the sample).
void Update () {
//Read bytes data from server stream
length = stream.Read(bytes, 0, bytes.Length);
if(length != 0){
// Convert byte array to string message
startedStreaming = true;
finishedStreaming = false;
serverMessage += Encoding.UTF8.GetString(bytes);
}
else{
finishedStreaming = true;
}
if(startedStreaming == true && finishedStreaming == true){
startedStreaming = false;
rendered = false;
readyToProcess = false;
StartCoroutine(DataStreaming());
}
if(readyToRender == true && rendered == false){
rendered = true;
Debug.Log("Rendering");
pcloud.updateBuffer();
}
}
private IEnumerator DataStreaming(){
//Convert bytes data to readable strings once finished receiving
if(finishedStreaming == true && readyToProcess == false){
if(renderer.enabled == false){
renderer.enabled = true;
}
newVectors = serverMessage.Split(new char[]{'\n'} );
Debug.Log("Message split");
pcloud._pointData = new PointCloudData.Point[newVectors.Length];
readyToProcess = true;
}
//Convert strings into numerical values and render once finished
if(readyToProcess == true && readyToRender == false){
readyToRender = true;
Debug.Log("rendering, "+ Time.realtimeSinceStartup);
Parallel.For(0, newVectors.Length, (coord) =>{
row = newVectors[coord].Split(new char[]{','});
float x = int.Parse(row[0]);
float y = int.Parse(row[1]);
float z = int.Parse(row[2]);
pcloud._pointData[coord].position = new Vector3((float)(x/pixelsPerUnit), (float)(y/1000f), (float)(z/pixelsPerUnit));
pcloud._pointData[coord].color = Pcx.PointCloudData.EncodeColor(dict[(int)y]);
});
}
if(readyToRender == true){
yield return new WaitForSeconds(10);
}
}
I am assuming that the mutlithreading is corrupting the data in some way. Is there anything I need to change or fix to get the correct result?
I have implemented a try-catch loop and discovered that a single line of corrupt data was the source of the problem. This appears to be due to the server-socket part of the program and so I won't discuss it further here, but the try-catch loop was a great solution to find where the problem was occurring, and to allow the program to continue despite errors occurring.
Related
My colleague and I working on project, where some physical devices are connected to Modbus interface(e.g. Lamp), and an desktop app where we sending requests to modbus using NModbus package, and also from time to time(e.g. after every 1 second) reading data from Modbus. We have a classic read/write conflict. Reading has no issue, but sometimes when we writing new value to modbus, the physical lamp going crazy and changing his state every 1 second.
Reading data from modbus is in different task, so do writing new values to modbus.
What we`ve tried:
lock critical section(only writing), and ignoring reading data when new value comes. After that we have a problem with queue and very slow working
CancellationToken - had no effect, or I writing it bad
Currently we have a class that collects property date of last state change(registered in IoC) and when new writing value comes, then we updating this property, and blocking from reading data from Modbus. Unfortunately this code sometimes working, sometimes not.
Please help. We are going crazy with this issue and we don`t know how to fix it.
Edit: I posting current code.
This is task, where we executing GetCurrentState handler
public void Start()
{
var cancellationToken = _cancellationTokenSource.Token;
Task.Run(async () =>
{
while (!cancellationToken.IsCancellationRequested)
{
await Task.Delay(ReadStateDelayInMiliseconds).ConfigureAwait(false);
if ((DateTime.Now - _lastCommandExecutionTimeContainer.LastCommandExecutionTime).TotalMilliseconds < _userCommandThresholdInMiliseconds)
continue;
try
{
await _service.GetCurrentState().ConfigureAwait(false);
}
catch (Exception ex)
{
Logger.Error($"Error while checking current state. Message '{ex.Message}', Stack trace: '{ex.StackTrace}'.");
}
}
}, cancellationToken);
}
This is GetCurrentState handler, where we reading data from Modbus
protected override IgnisLightState Handle(GetState request)
{
if ((DateTime.Now - _lastCommandExecutionTimeContainer.LastCommandExecutionTime).TotalMilliseconds <= _configuration.UserCommandThresholdInMiliseconds)
{
Logger.Debug($"Ignore before read state from lights, time after last execution: '{(DateTime.Now - _lastCommandExecutionTimeContainer.LastCommandExecutionTime).TotalMilliseconds}'.");
return _state;
}
var currentLightState = _state.DeepClone();
foreach (var head in currentLightState.Heads)
{
try
{
ushort startAddress = 0x0000;
ushort numberOfPointsToRead = 0x0006;
var values = _modbusMaster.ReadHoldingRegisters((byte)head.UniqueId, startAddress, numberOfPointsToRead);
var isOn = values[IgnisRegistry.On.Value];
var isEndo = values[IgnisRegistry.Endo.Value];
var isCentrum = values[IgnisRegistry.Centrum.Value];
var tempValue = values[IgnisRegistry.Temp.Value];
var illuminanceValue = values[IgnisRegistry.Vol.Value];
head.ColorValue = Convert.ToInt32(tempValue);
head.IlluminanceValue = Convert.ToInt32(illuminanceValue);
head.IsCentrumOn = Convert.ToBoolean(isCentrum);
head.IsEndoOn = Convert.ToBoolean(isEndo);
head.IsTurnedOn = Convert.ToBoolean(isOn);
if (currentLightState.CameraState != null &&
_configuration.CameraHeadId.HasValue &&
_configuration.CameraHeadId.Value == head.UniqueId)
{
var camMode = values[IgnisRegistry.Cam.Value];
currentLightState.CameraState.IsTurnedOn = Convert.ToBoolean(isOn);
currentLightState.CameraState.CurrentMode = (IgnisCameraMode)Convert.ToInt32(camMode);
}
}
catch (Exception ex)
{
Logger.ErrorFixed(ex, $"Error while getting data from headId {head.UniqueId}.");
}
}
if (_state.Equals(currentLightState)
|| (DateTime.Now - _lastCommandExecutionTimeContainer.LastCommandExecutionTime).TotalMilliseconds < _configuration.UserCommandThresholdInMiliseconds)
{
Logger.Debug($"Ignore after read state from lights, time after last execution: '{(DateTime.Now - _lastCommandExecutionTimeContainer.LastCommandExecutionTime).TotalMilliseconds}'.");
return _state;
}
foreach (var currentHeadState in currentLightState.Heads)
{
_lightHeadStateUpdater.UpdateState(currentHeadState);
}
Logger.Debug($"Broadcast new state to clients '{JsonConvert.SerializeObject(currentLightState)}'.");
_hubContext.Clients.All.StateChanged(currentLightState);
return currentLightState;
}
This is an Turn on lamp handler where we writing new value to modbus:
protected override Response Handle(TurnOn request)
{
_lastCommandExecutionTimeContainer.SetLastCommandExecutionTime(DateTime.Now);
if (request.HeadId <= 0
|| !_state.Heads.Any(x=>x.UniqueId == request.HeadId))
{
return ResponseFactory.FromError(Error.NotExist);
}
var headState = _state.Heads.Single(x=>x.UniqueId == request.HeadId);
if (headState.IsTurnedOn)
return ResponseFactory.FromError(Error.AlreadyAsRequested);
_modbusMaster.WriteSingleRegister((byte)request.HeadId, IgnisRegistry.On.Value, 0x0001);
headState.IsTurnedOn = true;
if (_state.CameraState != null &&
_ignisLightConfiguration.CameraHeadId.HasValue &&
_ignisLightConfiguration.CameraHeadId.Value == request.HeadId)
{
_state.CameraState.IsTurnedOn = true;
}
Logger.Trace($"Turn head lamp {request.HeadId} on.");
_hubContext.Clients.All.HeadStateChanged(headState);
return ResponseFactory.Success;
}
I have this function :
[HttpGet]
[Route("See/{OID}")]
public IActionResult See([FromRoute]long OID)
{
//time ham bayad chek bshe
orders order = _context.orders.FirstOrDefault(e => e.OID == OID);
lastViewed lv = _context.lastViewed.FirstOrDefault(e => e.UID.ToString() == User.Identity.Name);
if (DateTime.Compare(lv.sentTime.AddSeconds(order.seconds), GetUTCDateTime()) < 0)
return Content("1");
unViewed UV = _context.unViewed.FirstOrDefault(e => e.UID.ToString() == User.Identity.Name && e.OID == OID);
if (UV != null)
_context.unViewed.Remove(UV);
coins coin = _context.coins.FirstOrDefault(e => e.UID.ToString() == User.Identity.Name);
if (order.type > 50)
coin.Coin += order.seconds * 8;
else
coin.Coin += order.seconds;
order.view--;
if (order.view == 0)
{
var uv = _context.unViewed.Where(e => e.OID == OID);
foreach (unViewed uvv in uv)
_context.unViewed.Remove(uvv);
pastOrders po = new pastOrders
{
link = order.link,
OID = order.OID,
UID = order.UID
};
_context.pastOrders.Add(po);
_context.orders.Remove(order);
}
_context.SaveChanges();
return showlink();
}
the showlink() function is an IActionResult.the showlink() is fully independent from other codes.
my question is here how to first response the showlink() to user and after that response, run the other codes ?
thanks alot.
You can schedule the rest of the code to run on a separate thread. Note, though, that this is not entirely safe as you are not checking to see if the thread properly executed. In order to do that, you would need to add other checks to your code along with a way to be notified if something fails. Adopting an asynchronous model is a big undertaking and is the long term solution.
However, the following should unblock you for this particular case:
var result = showlink();
Task.Factory.StartNew(() => {
// Rest of your code that needs to run in the background.
});
return result;
I'm developing a poker app i almost have it done and im looking for improvements and 1 of the things i wonder about is should i change my main looping method method ? Currently it's looping by using tail recursive call. However friend of mine suggested me to switch it to a iteration since it's using a while loop and loop's don't require stack space. Here's my code as it is now.
private async Task Turns()
{
_turns = ReturnTurns();
GC.KeepAlive(Updates);
if (!Player.FoldTurn && Player.Chips > 0)
{
if (Player.Turn)
{
SetPlayerStuff(true);
Call -= Player.PreviousCall;
_up = int.MaxValue;
_turnCount++;
Bot1.Turn = true;
_restart = true;
}
}
if (!Player.Turn)
{
await Flip(0);
}
if (Player.FoldTurn || !Player.Turn || Player.Chips <= 0)
{
Call = TempCall;
if (StatusLabels[Player.EnumCasted].Contains(RepetitiveVariables.Fold))
{
Bot1.Turn = true;
}
SetPlayerStuff(false);
Bot1 = (Bot)await RotateTurns(Bot1, Bot1.EnumCasted);
Bot2 = (Bot)await RotateTurns(Bot2, Bot2.EnumCasted);
Bot3 = (Bot)await RotateTurns(Bot3, Bot3.EnumCasted);
Bot4 = (Bot)await RotateTurns(Bot4, Bot4.EnumCasted);
Bot5 = (Bot)await RotateTurns(Bot5, Bot5.EnumCasted);
_restart = false;
}
if (!_restart)
{
await Turns();
}
}
That's how i think it should look's like with a loop:
private async Task Turns()
{
while (true)
{
_turns = ReturnTurns();
GC.KeepAlive(Updates);
if (!Player.FoldTurn && Player.Chips > 0)
{
if (Player.Turn)
{
SetPlayerStuff(true);
Call -= Player.PreviousCall;
_up = int.MaxValue;
_turnCount++;
Bot1.Turn = true;
_restart = true;
}
}
if (!Player.Turn)
{
await Flip(0);
}
if (Player.FoldTurn || !Player.Turn || Player.Chips <= 0)
{
Call = TempCall;
if (StatusLabels[Player.EnumCasted].Contains(RepetitiveVariables.Fold))
{
Bot1.Turn = true;
}
SetPlayerStuff(false);
Bot1 = (Bot) await RotateTurns(Bot1, Bot1.EnumCasted);
Bot2 = (Bot) await RotateTurns(Bot2, Bot2.EnumCasted);
Bot3 = (Bot) await RotateTurns(Bot3, Bot3.EnumCasted);
Bot4 = (Bot) await RotateTurns(Bot4, Bot4.EnumCasted);
Bot5 = (Bot) await RotateTurns(Bot5, Bot5.EnumCasted);
_restart = false;
}
if (!_restart)
{
continue;
}
break;
}
}
Generally, the JIT is not able to replace recursion with a loop. This is a fairly esoteric optimization scenario.
Here, this does not even come into play because an async method uses very different call mechanisms internally.
This code will consume "stack space" proportional to the recursion depth. (It's not necessarily stack space with async methods. Could be heap space in the form of a linked list.)
From a code quality standpoint I find the loop vastly preferable because recursion is not what most people are used to. Here, there really is no algorithmic need for recursion. Seems like the wrong tool for the job. I think you have used recursion as a replacement for "goto" here because all this does is jump back to the beginning of the method.
You can make the jump condition a little cleaner:
if (!_restart) break;
As part of my school project I'm trying to link two tables to decrease the amount of data stored in one table so I wanted to link my "Scores" class with my "CorrectAnswers" class via the ObjectID. However since the tasks are asynchronous, by the time one task is done saving, the other task has already begun or also finished saving and so the ObjectID returns as null.
Here's the code I'm using:
public void SaveScore()
{
ParseObject SendScore = new ParseObject("Scores");
SendScore["Score"] = CheckAnswer.score;
SendScore["user"] = ParseObject.CreateWithoutData("_User", ParseUser.CurrentUser.ObjectId);
SendScore["TestMode"] = MainMenu.testmode;
SendScore["TotalQuestions"] = QuestionCreation.TotalQuestions;
SendScore["CorrectQuestions"] = CheckAnswer.CorrectQuestions;
SendScore.SaveAsync().ContinueWith(t =>
{
ScoreObjectId = SendScore.ObjectId;
});
ParseObject SendCorrectTopics = new ParseObject("CorrectAnswers");
SendCorrectTopics["Score"] = SendScore.ObjectId;
for (int i = 0; i <= 9; i++)
{
string Topic = "Topic" + (i + 1).ToString();
SendCorrectTopics[Topic] = CheckAnswer.CorrectTopics[i];
}
SendCorrectTopics.SaveAsync();
SceneManager.LoadScene(0);
}
How would I be able to make the second save hold until the first save has finished? I'm somewhat new to C# and so don't quite know all it's features yet. I've looked into "await" but unity doesn't seem to like that. Any help would be greatly appreciated!
Thanks in advance,
EDIT: Okay, after a bit more reading on Unity's coroutines, I found a much better way of checking that only relies on checking when needed:
IEnumerator CheckSave()
{
while(ScoreObjectId == null & !DoneSave))
{
print("Running");
yield return new WaitForSeconds(0.5f);
}
DoneSave = false;
SaveTotalTopics();
}
This seems like a much better way of doing it.
Well, it seems the answer was something I've already done before, even if it is a little ugly.
Using Unity's update function I created a check to make sure the ObjectID is not null and the previous save had completed, as so:
void Update () {
if (ScoreObjectId != null & DoneSave)
{
DoneSave = false;
SaveTotalTopics();
}
Thus splitting it into two saves and creating:
public void SaveScore()
{
ParseObject SendScore = new ParseObject("Scores");
SendScore["Score"] = CheckAnswer.score;
SendScore["user"] = ParseObject.CreateWithoutData("_User", ParseUser.CurrentUser.ObjectId);
SendScore["TestMode"] = MainMenu.testmode;
SendScore["TotalQuestions"] = QuestionCreation.TotalQuestions;
SendScore["CorrectQuestions"] = CheckAnswer.CorrectQuestions;
Task SendingScores = SendScore.SaveAsync().ContinueWith(t =>
{
if (t.IsFaulted || t.IsCanceled)
{
DoneSave = false;
print(t.Exception);
}
else
{
DoneSave = true;
print("Setting object ID!");
ScoreObjectId = SendScore.ObjectId;
print(ScoreObjectId);
}
});
}
void SaveTotalTopics()
{
for (int i = 0; i <= 9; i++)
{
string Topic = "Topic" + (i + 1).ToString();
SendCorrectTopics[Topic] = CheckAnswer.CorrectTopics[i];
}
SendCorrectTopics["UserScore"] = ParseObject.CreateWithoutData("Scores", ScoreObjectId);
SendCorrectTopics.SaveAsync().ContinueWith(t =>
{
if(t.IsFaulted || t.IsCanceled)
{
print(t.Exception);
}
else
{
print("Saved!");
}
});
}
I'd also forgotten to use ParseObject.CreateWithoutData() so my first code snippet wouldn't have worked even if I'd found a better method...
So, although I'm not happy with the final result, at least it works and I don't think running an if statement every frame should significantly impact on my game's performance.
Why not use a bool and a while loop?
public IEnumerator SaveScore()
{
bool canContinue = false;
ParseObject SendScore = new ParseObject("Scores");
SendScore["Score"] = CheckAnswer.score;
SendScore["user"] = ParseObject.CreateWithoutData("_User", ParseUser.CurrentUser.ObjectId);
SendScore["TestMode"] = MainMenu.testmode;
SendScore["TotalQuestions"] = QuestionCreation.TotalQuestions;
SendScore["CorrectQuestions"] = CheckAnswer.CorrectQuestions;
SendScore.SaveAsync().ContinueWith(t =>
{
ScoreObjectId = SendScore.ObjectId;
//set the bool canContinue to true because the first portion of code has finished running
canContinue = true;
});
//wait while the canContinue bool is false
while(!canContinue){
yield return null;
}
//continue your parse code
ParseObject SendCorrectTopics = new ParseObject("CorrectAnswers");
SendCorrectTopics["Score"] = SendScore.ObjectId;
for (int i = 0; i <= 9; i++)
{
string Topic = "Topic" + (i + 1).ToString();
SendCorrectTopics[Topic] = CheckAnswer.CorrectTopics[i];
}
SendCorrectTopics.SaveAsync();
SceneManager.LoadScene(0);
return null;
}
I am trying to receive objects with TCP using C# and serialization. I am receiving objects constantly and each object is sent to a new task. I chose not to use threads because its too expensive. The problem is that if I am receiving only 1 object at a time everything goes just fine but if I am trying to receive more than 1 object, after a few seconds I am getting:
"the input stream is not a valid binary format. the starting contents (in bytes) are: ..."
This is my listening function:
public void Listen()
{
try
{
TcpObject tcpObject = new TcpObject();
IFormatter formatter = new BinaryFormatter();
bool offline = true;
Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Normal,
new Action(() => offline = Offline));
while (!offline)
{
tcpObject = (TcpObject)formatter.Deserialize(serverStream);
if (tcpObject.Command == Command.Transfer)
{
#region Task
Task.Factory.StartNew(() =>
{
SentAntenna sentAntenna = (SentAntenna)tcpObject.Object;
string antennaName = sentAntenna.Name;
if (MainWindow.SpectrumList.ContainsKey(antennaName))
{
PointCollection pointCollection = new PointCollection();
float minChan = sentAntenna.Min;
float maxChan = sentAntenna.Max;
if (MainWindow.SpectrumList[antennaName].spectrumViewModel.AbsoluteMinimum == -1)
{
Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Normal,
new Action(delegate
{
MainWindow.SpectrumList[antennaName].spectrumViewModel.AbsoluteMinimum = minChan;
MainWindow.SpectrumList[antennaName].spectrumViewModel.AbsoluteMaximum = maxChan;
MainWindow.SpectrumList[antennaName].spectrumViewModel.TBMinRange = minChan.ToString();
MainWindow.SpectrumList[antennaName].spectrumViewModel.TBMaxRange = maxChan.ToString();
MainWindow.SpectrumList[antennaName].spectrumViewModel.MinRange = minChan;
MainWindow.SpectrumList[antennaName].spectrumViewModel.MaxRange = maxChan;
MainWindow.SpectrumList[antennaName].spectrumViewModel.UpdateRange();
}));
}
float gap = maxChan - minChan;
foreach (Frequency f in sentAntenna.Frequencies)
{
float chan = ((f.Channel - minChan) / gap) * 310;
float inten = ((f.Intensity - 1) / 599) * 100;
pointCollection.Add(new Point(chan, inten));
}
pointCollection.Freeze();
Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Normal,
new Action(() => MainWindow.SpectrumList[antennaName].spectrumViewModel.AllAntennaPoints = pointCollection.Clone()));
}
Thread.Sleep(50);
});
#endregion
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message); // raise an event
}
}
What am I doing wrong?
Try moving
SentAntenna sentAntenna = (SentAntenna)tcpObject.Object;
to the line before the StartNew(). I believe this will fix your issue.
I don't think you want concurrent access to the tcpObject, since it's global to all the tasks.
Alternatively you could instantiate the TcpObject inside the while loop, which would then keep it local to each task.
There are several reasons for this error:
When two objects concurently writes to one connection
When somthing goes wrong with serverStream: stream have received a part of data or received 0 length data
You concurently acces to tcpObject. it's a bad idea.